Positioning method and system

Abstract

The present application discloses a positioning method and system, which relate to the field of Bluetooth positioning technology. The positioning method comprises: obtaining multiple RSSI values ​​between each Bluetooth beacon and a terminal; filtering and averaging the multiple RSSI values ​​in sequence to determine a corresponding reference RSSI value; determining the distance between each Bluetooth beacon and the terminal according to the reference RSSI value between each Bluetooth beacon and the terminal; determining the coordinate position of the terminal according to the distances between the multiple Bluetooth beacons and the terminal; when the coordinate position of the terminal is within a preset coordinate range, the terminal makes an alarm action and sends a corresponding alarm signal to an external terminal; the present application aims to solve the technical problem that a vehicle cannot be accurately positioned when entering a scene blocked by an obstruction.

Description

Technical Field

[0001] The present application relates to the field of Bluetooth positioning technology, and in particular to a positioning method and system. Background Art

[0002] The current mainstream vehicle tracking technology mainly relies on the Global Positioning System (GPS), which has the advantages of wide coverage, easy use, large number of mobile terminals and all-weather operation. However, GPS also has defects in practical applications. In specific environments with obstructions such as tunnels, underground garages and mountain roads, satellite signals will be blocked by obstructions, so that GPS may not work properly, thus forming a positioning blind spot. Summary of the invention

[0003] The main purpose of the present application is to provide a positioning method and system, which aims to solve the technical problem that a vehicle cannot be accurately positioned when entering a scene where there are obstructions.

[0004] To achieve the above-mentioned purpose, the present application proposes a positioning method, which is applied to a positioning system, wherein the positioning system includes a plurality of positioning areas and a terminal arranged in a vehicle, wherein the plurality of positioning areas are arranged on a lane in sequence along the length direction of the lane, wherein the positioning area includes a plurality of Bluetooth beacons respectively installed on the left boundary line, the middle dividing line and the right boundary line of the lane, wherein the terminal establishes a Bluetooth communication connection with the plurality of Bluetooth beacons, and the method includes:

[0005] Acquire multiple groups of RSSI values ​​between the multiple Bluetooth beacons in the positioning area where the vehicle enters and the terminal;

[0006] Determine the distances between the multiple groups of Bluetooth beacons and the terminal according to the multiple groups of RSSI values;

[0007] Determining multiple reference coordinates of the terminal according to the distances between the multiple groups of Bluetooth beacons and the terminal;

[0008] Determining the actual coordinates of the terminal according to the plurality of reference coordinates;

[0009] Wherein, the positioning area includes at least six Bluetooth beacons.

[0010] In one embodiment, determining the actual coordinates of the vehicle according to the reference coordinates of the multiple terminals includes:

[0011] Calculate the difference between the horizontal coordinates of the reference coordinates and the horizontal coordinates of the Bluetooth beacon located on the left boundary line and the horizontal coordinates of the Bluetooth beacon located on the right boundary line to determine a plurality of first horizontal distances and a plurality of second horizontal distances;

[0012] comparing a plurality of the first lateral distances and a plurality of the second lateral distances with a lane width respectively;

[0013] When the first lateral distance corresponding to any one of the reference coordinates is smaller than the lane width and the corresponding second lateral distance is larger than the lane width, a first count is performed and the abscissa of the reference coordinate is marked as a first abscissa;

[0014] When the first lateral distance corresponding to any one of the reference coordinates is greater than the lane width and the corresponding second lateral distance is less than the lane width, performing a second count and marking the abscissa of the reference coordinate as a second abscissa;

[0015] When the ratio of the value of the first count to the number of the reference coordinates is greater than a preset percentage, it is determined that the vehicle is located in the left lane; when the ratio of the value of the second count to the number of the reference coordinates is greater than a preset percentage, it is determined that the vehicle is located in the right lane;

[0016] When it is determined that the vehicle is located in the left lane, calculating an average value of a plurality of the first horizontal coordinates to determine the horizontal coordinate of the actual coordinate of the terminal;

[0017] When it is determined that the vehicle is located in the right lane, an average value of a plurality of the second horizontal coordinates is calculated to determine the horizontal coordinate of the actual coordinate of the terminal.

[0018] In one embodiment, the obtaining of multiple groups of RSSI values ​​between the multiple Bluetooth beacons in the positioning area where the vehicle enters and the terminal includes: obtaining RSSI measurement values ​​at a current moment;

[0019] Based on the RSSI measurement value at the current moment and the RSSI predicted change rate at the current moment, calculate the RSSI predicted value at the next moment;

[0020] The RSSI measurement value at the next moment is obtained, and the RSSI prediction value at the next moment is combined with the RSSI measurement value at the next moment to determine the RSSI filter value at the next moment.

[0021] In one embodiment, the method for obtaining the predicted RSSI change rate at the current moment includes:

[0022] Determine the change value of the RSSI prediction change rate at the current moment according to the RSSI prediction value at the previous moment and the RSSI filter value at the previous moment;

[0023] The change value of the RSSI predicted change rate at the current moment is added to the RSSI predicted change rate at the previous moment to determine the RSSI predicted change rate at the current moment.

[0024] In one embodiment, the acquiring of multiple groups of RSSI values ​​between the multiple Bluetooth beacons in the positioning area into which the vehicle enters and the terminal comprises:

[0025] Detecting the multiple groups of RSSI values ​​to determine the state of each group of RSSI values; wherein the state includes a lost state and a complete state;

[0026] When it is determined that any one group of RSSI values ​​is lost, an average value of the RSSI value of the previous group and the RSSI value of the subsequent group is calculated to compensate for the lost RSSI value.

[0027] In one embodiment, the positioning system further includes a plurality of detection areas, which are sequentially arranged on the lane along the length direction of the lane; the detection area includes a first infrared receiver, a second infrared receiver and an infrared transmitter located on the same straight line, and the straight line forms a preset angle with the straight line in the length direction of the lane; the infrared transmitter is arranged on the middle dividing line and is located at adjacent positions of adjacent positioning areas, or at non-adjacent positions of the positioning areas; the first infrared receiver is arranged on the left boundary line, and the second infrared receiver is arranged on the right boundary line; wherein the positioning area where the first infrared receiver is located is the next positioning area after the positioning area where the second infrared receiver is located;

[0028] The positioning method further includes:

[0029] When any one of the first infrared receivers is triggered, control the plurality of Bluetooth beacons in the previous location zone of the location zone where the first infrared receiver is located to send Bluetooth broadcast signals;

[0030] When any one of the second infrared receivers is triggered, control a plurality of the Bluetooth beacons in a subsequent location zone of the location zone where the second infrared receiver is located to send Bluetooth broadcast signals;

[0031] When any one of the first infrared receivers is not triggered, the plurality of Bluetooth beacons in the previous positioning zone of the positioning zone where the first infrared receiver is located are controlled to stop working;

[0032] When any one of the first infrared receivers is not triggered, the plurality of Bluetooth beacons in the next positioning zone where the first infrared receiver is located are controlled to stop working.

[0033] In one embodiment, the positioning method further includes:

[0034] Establishing a change curve of RSSI values ​​between the plurality of Bluetooth beacons in the plurality of positioning areas and the terminal;

[0035] When the RSSI value between any one of the Bluetooth beacons and the terminal reaches a maximum value, it is determined that the vehicle enters the positioning area where the Bluetooth beacon whose RSSI value reaches the maximum value is located.

[0036] In one embodiment, determining a plurality of reference coordinates of the terminal according to the distances between the plurality of groups of Bluetooth beacons and the terminal comprises:

[0037] Randomly select three Bluetooth beacons that are not in the same straight line from the plurality of Bluetooth beacons as a group, and determine N combinations;

[0038] The distances between the three Bluetooth beacons in N combinations and the terminal are processed based on the three-side centroid positioning algorithm to determine N centroid coordinates;

[0039] The N centroid coordinates are fused to determine the reference coordinates of the terminal.

[0040] In one embodiment, fusing the N centroid coordinates to determine the reference coordinates of the terminal includes:

[0041] Determine weighting factors of the N combinations based on the distances between the three Bluetooth beacons of the N combinations and the terminal;

[0042] Combining the N combined weighting factors with the abscissas and ordinates of the N centroid coordinates one by one, respectively, to determine N weighted abscissas and N weighted ordinates;

[0043] An average value of the N weighted horizontal coordinates and an average value of the N weighted vertical coordinates are calculated respectively to determine the reference coordinates of the terminal.

[0044] In addition, to achieve the above-mentioned purpose, the present application also proposes a positioning system, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the positioning method described above; the positioning system also includes multiple positioning areas and a terminal arranged in a vehicle, wherein the multiple positioning areas are arranged in sequence on the lane, and the positioning area includes multiple Bluetooth beacons respectively installed on the left boundary line, the middle dividing line, and the right boundary line of the lane, and the terminal establishes a Bluetooth communication connection with the multiple Bluetooth beacons.

[0045] One or more technical solutions proposed in this application have at least the following technical effects:

[0046] The positioning method of the present application is applied to a positioning system, the positioning system includes multiple positioning areas and a terminal, the multiple positioning areas are sequentially arranged on the lane along the length direction of the lane, the positioning area includes multiple Bluetooth beacons respectively installed on the left boundary line, the middle lane and the right boundary line, and the positioning method includes: obtaining multiple groups of RSSI values ​​between the multiple Bluetooth beacons in the positioning area where the vehicle enters and the terminal; determining the first distance between the multiple groups of multiple Bluetooth beacons and the terminal according to the multiple groups of RSSI values; determining multiple reference coordinates of the terminal according to the distance between the multiple groups of multiple Bluetooth beacons and the terminal; determining the actual coordinates of the terminal according to the multiple reference coordinates. With such a setting, in actual applications, multiple positioning areas can be sequentially installed on roads in scenes such as tunnels, urban high-rise dense areas, mountain roads and underground parking lots. When the vehicle is driving, each positioning area will locate the vehicle when the vehicle passes by, thereby accurately locating the actual position of the vehicle, compensating for the defect that the GPS positioning system cannot accurately locate in scenes with obstacles (tunnels, urban high-rise dense areas, mountain roads and underground parking lots). BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0048] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0049] Figure 1 A schematic diagram of a flow chart provided for an embodiment of a positioning method of the present application;

[0050] Figure 2 A flowchart diagram of another embodiment of the positioning method of the present application is provided;

[0051] Figure 3 A flowchart diagram of another embodiment of the positioning method of the present application is provided;

[0052] Figure 4 A flowchart diagram of another embodiment of the positioning method of the present application is provided;

[0053] Figure 5 A flowchart diagram of another embodiment of the positioning method of the present application is provided;

[0054] Figure 6 A flowchart diagram of another embodiment of the positioning method of the present application is provided;

[0055] Figure 7 A flowchart diagram of another embodiment of the positioning method of the present application is provided;

[0056] Figure 8 A flowchart diagram of another embodiment of the positioning method of the present application is provided;

[0057] Fig. 9 A schematic diagram of the distribution of multiple Bluetooth beacons in the positioning method of this application;

[0058] Fig.10 Another schematic diagram of the distribution of multiple Bluetooth beacons in the positioning method of this application.

[0059] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0060] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0061] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0062] The current mainstream vehicle tracking technology mainly relies on the Global Positioning System (GPS), which has the advantages of wide coverage, easy use, large number of mobile terminals and all-weather operation. However, GPS also has defects in practical applications. In specific environments with obstructions such as tunnels, underground garages and mountain roads, satellite signals will be blocked by obstructions, so that GPS may not work properly, thus forming a positioning blind spot.

[0063] To this end, the main purpose of the present application is to provide a positioning method and system, which aims to solve the technical problem that a vehicle cannot be accurately positioned when entering a scene where there are obstructions.

[0064] refer to Figure 1 In one embodiment of the present application, a positioning method is applied to a positioning system, the positioning system comprising a plurality of positioning areas and a terminal arranged in a vehicle, the plurality of positioning areas being arranged in sequence on a lane along the length direction of the lane, the positioning area comprising a plurality of Bluetooth beacons respectively installed on a left boundary line, a middle dividing line and a right boundary line of the lane, the terminal establishing a Bluetooth communication connection with the plurality of Bluetooth beacons;

[0065] It should be noted that the positioning area includes at least six Bluetooth beacons, and three of the multiple Bluetooth beacons are installed on the left boundary line, the middle dividing line and the right boundary line of the lane respectively, and the straight line formed by the three Bluetooth beacons is perpendicular to the length direction of the lane. Fig. 9, ①~⑨ are all Bluetooth beacons, the Bluetooth beacons of ①~⑥ constitute one positioning area, and the Bluetooth beacons of ④~⑨ constitute the other positioning area.

[0066] The method comprises:

[0067] Step S100: Acquire multiple groups of RSSI values ​​between multiple Bluetooth beacons in the positioning area where the vehicle enters and the terminal;

[0068] It should be noted that the Bluetooth beacon is deployed on the lane indicator line and is responsible for periodically sending Bluetooth broadcast signals to provide positioning information. The Bluetooth mobile terminal is installed on the vehicle to be located, which can be a mobile phone or a Bluetooth adapter or other device with Bluetooth broadcast receiving function. The Bluetooth mobile terminal parses the longitude and latitude information and RSSI value from the Bluetooth beacon broadcast to provide data source for the positioning algorithm.

[0069] In order to ensure that the terminal receives enough data, the Bluetooth beacon is set to periodically send a Bluetooth broadcast signal every 100 milliseconds, and a terminal scanning cycle is set at 0.3 seconds to 1 second, so that the number of RSSI values ​​obtained by the terminal in one scanning cycle is 3 to 10 groups, thereby avoiding positioning errors caused by environmental interference (such as multipath effects, obstacles, etc.). In sections with fast speeds such as highways and urban expressways, the fixed interval between adjacent Bluetooth beacons in the length direction of the lane can be set to 20-25m, ensuring that even if the vehicle moves at high speed, it can communicate with multiple Bluetooth beacons in a short time and obtain continuous positioning data; the fixed spacing in low-speed sections such as urban roads can be set to 10-15m, which helps provide more precise positioning information when the vehicle is driving at low speed.

[0070] It should be noted that when a vehicle enters an environment with obstructions, the Bluetooth broadcast signal sent by the Bluetooth beacon to the terminal is easily absorbed, reflected and refracted by the obstacles, so that the RSSI value received by the terminal is prone to instability or large fluctuations. Therefore, a suitable filtering algorithm is needed to process the RSSI value received by the terminal. Commonly used filtering algorithms include mean filtering, median filtering, Gaussian filtering, etc. The reference RSSI value obtained after filtering can reflect the actual signal strength.

[0071] Among them, the mean filter algorithm performs arithmetic mean operation on the data. The algorithm is relatively simple and is more suitable for filtering in the case of random interference. When the collected RSSI values ​​are all one-dimensional, the median filter algorithm arranges the sampled RSSI values ​​from small to large, selects the middle value as the filter output, and determines the reference RSSI value. The advantage of the median filter algorithm is that it denoises the data while retaining the edge data. The Kalman filter algorithm uses the RSSI value of the previous moment and the RSSI value collected by the terminal at the current moment to update the estimate of the state variable, thereby obtaining the best estimate of the RSSI value at the current moment. The Gaussian filter algorithm can calculate the average value μ and standard deviation σ of multiple RSSI values, select RSSI values ​​in the interval (μ-σ, μ+σ), and average the selected multiple RSSI values ​​to determine the reference RSSI value.

[0072] Step S200: determining the distances between the multiple groups of Bluetooth beacons and the terminal according to the multiple groups of RSSI values;

[0073] It should be noted that the positioning method of this application can determine the distance d between each Bluetooth beacon and the terminal according to the formula relationship between the RSSI value and the distance. The formula relationship is: ; Substitute the RSSI value of each Bluetooth beacon obtained by the terminal into the above formula to calculate the distance between each Bluetooth beacon and the terminal. Where d is the distance between the Bluetooth beacon and the terminal, A is the RSSI value when the distance between the Bluetooth beacon and the terminal is 1m, n is the environmental attenuation factor, and RSSI is the signal strength of the Bluetooth beacon received by the terminal. For example, assuming a set of specific values: RSSI=-70dBn, A=-60dBn, n=2, substitute it into the above formula, and the distance between the corresponding Bluetooth beacon and the terminal can be calculated to be 3.16m. In order to accurately perform positioning calculations and avoid erroneous or unreliable distance estimates due to weak signals, -100dBn can be set as the minimum point, and the RSSI value is only used for calculations when it is higher than -100dBn.

[0074] Step S300: determining a plurality of reference coordinates of the terminal according to the distances between the plurality of groups of Bluetooth beacons and the terminal;

[0075] The positioning method of this application can calculate the coordinate position of the terminal through the three-side centroid algorithm, refer to Figure 2 , the specific steps are:

[0076] Step S310: randomly selecting three Bluetooth beacons that are not in the same straight line from the plurality of Bluetooth beacons as a group, and determining N combinations;

[0077] It is understandable that different combinations can estimate the terminal coordinates from different angles, reducing the positioning deviation caused by individual beacon errors.

[0078] Step S320: Processing the distances between the three Bluetooth beacons in N combinations and the terminal based on a three-sided centroid positioning algorithm to determine N centroid coordinates;

[0079] The three-sided centroid algorithm is specifically as follows: draw a circle with the coordinates of the Bluetooth beacon as the point and the distance as the radius. In an ideal situation where errors are not considered, the terminal is at the intersection of the three circles with the Bluetooth beacon as the point. The coordinates of the intersection, that is, the coordinate position of the terminal, can be calculated based on the coordinates of the three Bluetooth beacons and the distances between them and the terminal. However, due to measurement errors, signal fluctuations and other reasons, the three circles often cannot intersect at one point, but intersect in pairs. The terminal is in a triangle formed by the intersection of the two circles. In this case, the coordinates of the three intersections are calculated in turn based on the radii of the two intersecting circles and the points of the two circles, and the coordinates of the three intersections are averaged to determine the coordinate position of the terminal. For example, assuming that the coordinates of the three Bluetooth beacons are (x1, y1), (x2, y2) and (x3, y3), and the radii are d1, d2 and d3, the coordinates of the three intersections can be calculated according to the following formula:

[0080] ;

[0081] ;

[0082] ; xo1, xo2 and xo3 are the horizontal coordinates of the three intersection points, and yo1, yo2 and yo3 are the vertical coordinates of the three intersection points. For example, the process of calculating the intersection point (xo1, yo1) is as follows: List the following set of equations:

[0083] First equation: ;

[0084] Second equation: ;

[0085] Subtract the first equation from the second equation to get the equation of the line where the two intersection points of the circle with (x1, y1) as the center and the circle with (x2, y2) as the center are located. Substitute the equation of the line into the first equation or the second equation to get the coordinates of the two intersection points, and then filter out the coordinates of the intersection point closer to the coordinates (x3, y3) to get (xo1, yo1). Similarly, (xo2, yo2) and (xo3, yo3) can also be calculated according to the above process, which will not be repeated here.

[0086] The centroid coordinates (xt, yt) are calculated based on the horizontal and vertical coordinates of the three intersection points:

[0087] , .

[0088] It should be noted that the radii d1, d2 and d3 are the distances between the three Bluetooth coordinates and the terminal respectively, and the coordinates of the three Bluetooth beacons are all known.

[0089] Step S330: Fuse the N centroid coordinates to determine the reference coordinates of the terminal.

[0090] It should be noted that each centroid coordinate is calculated based on the distance between each group of Bluetooth beacons and the terminal in the N combinations in step 310, and each centroid coordinate may be slightly different due to various factors (such as signal interference, environmental changes, etc.). By fusing multiple centroid coordinates, these differences can be averaged out to obtain an estimate that is closer to the actual position. The fusion method can include advanced algorithms such as weighted averaging and Kalman filtering to make full use of the information provided by multiple centroid coordinates.

[0091] It can be understood that the reference coordinates calculated in step S330 are calculated by the terminal based on one set of RSSI values ​​received in a scanning cycle, for example, one of the three sets of RSSI values ​​received when the scanning cycle is 0.3S. The terminal processes the distances between multiple sets of multiple Bluetooth beacons and the terminal one by one based on steps 310 to 330 to determine multiple reference coordinates of the terminal.

[0092] Step S400: Determine the actual coordinates of the terminal according to the multiple reference coordinates.

[0093] It should be noted that the horizontal coordinates and the vertical coordinates of the multiple reference coordinates are directly averaged and the average value is used as the actual coordinate of the terminal.

[0094] Specifically, the positioning method of the present application is applied to a positioning system, the positioning system includes multiple positioning areas and a terminal, the multiple positioning areas are sequentially arranged on the lane, the positioning area includes multiple Bluetooth beacons respectively installed on the left boundary line, the middle lane and the right boundary line, and the positioning method includes: obtaining multiple groups of RSSI values ​​between the multiple Bluetooth beacons in the positioning area where the vehicle enters and the terminal; determining the first distance between the multiple groups of multiple Bluetooth beacons and the terminal according to the multiple groups of RSSI values; determining multiple reference coordinates of the terminal according to the distance between the multiple groups of multiple Bluetooth beacons and the terminal; determining the actual coordinates of the terminal according to the multiple reference coordinates. With such a setting, in actual applications, multiple positioning areas can be sequentially installed on roads in scenes such as vehicles entering tunnels, urban high-rise dense areas, mountain roads and underground parking lots. During the driving process of the vehicle, each positioning area will locate the vehicle when the vehicle passes by, thereby accurately locating the actual position of the vehicle, compensating for the defect that the GPS positioning system cannot accurately locate in scenes with obstacles (tunnels, urban high-rise dense areas, mountain roads and underground parking lots).

[0095] Since the Bluetooth broadcast signal received by the terminal during the driving process of the vehicle will be affected by various interference factors, such as environmental noise, multipath effect, signal attenuation, etc., these factors may cause errors in the RSSI value parsed by the terminal. When there are significant errors in multiple RSSI values ​​in one set of RSSI values, the final calculated reference coordinates will deviate from the actual coordinates of the terminal. Specifically, when the vehicle is driving on the inner side of the left lane, the terminal should be located in the left lane, but due to interference with the signals emitted by some Bluetooth beacons, or problems in the terminal receiving and processing these signals, one or more sets of RSSI values ​​will deviate. These deviated RSSI values ​​will be treated as accurate data in the subsequent calculation process, resulting in the calculated reference coordinates deviating from the actual position of the terminal. In extreme cases, this deviation may cause the calculated terminal coordinates to be incorrectly located in the right lane, although the vehicle is actually still driving in the left lane. This incorrect positioning not only affects the accuracy of the vehicle navigation system, but may also mislead traffic monitoring and safety systems, thereby causing potential safety risks.

[0096] refer to Figure 3 In one embodiment of the present application, determining the actual coordinates of the vehicle according to the reference coordinates of the multiple terminals includes:

[0097] Step S410: calculating the difference between the horizontal coordinates of the reference coordinates and the horizontal coordinates of the Bluetooth beacon located on the left boundary line and the horizontal coordinates of the Bluetooth beacon located on the right boundary line, so as to determine a plurality of first horizontal distances and a plurality of second horizontal distances;

[0098] It should be noted that the first horizontal distance is the horizontal distance between the reference coordinate and the left boundary line, and the second horizontal distance is the horizontal distance between the reference coordinate and the right boundary line.

[0099] Step S420: comparing the plurality of first lateral distances and the plurality of second lateral distances with the lane width respectively;

[0100] Step S430: when the first lateral distance corresponding to any one of the reference coordinates is smaller than the lane width and the corresponding second lateral distance is larger than the lane width, performing a first count and marking the abscissa of the reference coordinate as a first abscissa;

[0101] When the first lateral distance corresponding to any one of the reference coordinates is greater than the lane width and the corresponding second lateral distance is less than the lane width, performing a second count and marking the abscissa of the reference coordinate as a second abscissa;

[0102] It should be noted that, if the first lateral distance corresponding to any reference coordinate is less than the lane width and the second lateral distance corresponding to the reference coordinate is greater than the lane width, it means that the reference coordinate is located in the left lane. Similarly, if the second lateral distance corresponding to any reference coordinate is less than the lane width and the second lateral distance corresponding to the reference coordinate is greater than the lane width, it means that the reference coordinate is located in the right lane. Fig. 9 , establish coordinates with Bluetooth beacon ② as the origin, assuming that each coordinate unit is 1m, one of the reference coordinates of the terminal is (3,8), the horizontal coordinates of Bluetooth beacon ① and Bluetooth beacon ④ are both 4, and the horizontal coordinates of Bluetooth beacon ③ and Bluetooth beacon ⑥ are both -4, then the horizontal distance between the terminal and the right boundary line is |3-4|=1m, and the horizontal distance between the terminal and the left boundary line is 3-(-4)=7m. Since the first horizontal distance (1m) of this reference coordinate is less than the lane width (4m), and the second horizontal distance (7m) is greater than the lane width (4m), the reference coordinate is located in the right lane.

[0103] Step S440: When the ratio of the value of the first count to the number of the reference coordinates is greater than a preset percentage, it is determined that the vehicle is located in the left lane; when the ratio of the value of the second count to the number of the reference coordinates is greater than a preset percentage, it is determined that the vehicle is located in the right lane;

[0104] It should be noted that the preset percentage can be set between 70% and 90%. When the ratio of the value of the first count to the number of reference coordinates is greater than 70%, it means that most of the calculated reference coordinates are located in the left lane, and a small part of the reference coordinates may have errors in the calculation process due to interference factors, resulting in a small part of the reference coordinates being located in the right lane. In this regard, the small part of the reference coordinates is omitted, and the majority of the reference coordinates are used as a reference to make the actual coordinates calculated in the end more accurate. Similarly, when the ratio of the value of the second count to the number of reference coordinates is greater than 70%, it means that most of the calculated reference coordinates are located in the right lane, and a small part of the reference coordinates may have errors in the calculation process due to interference factors, resulting in a small part of the reference coordinates being located in the left lane. In this regard, the small part of the reference coordinates is omitted, and the majority of the reference coordinates are used as a reference to make the actual coordinates calculated in the end more accurate.

[0105] Step S450: When it is determined that the vehicle is located in the left lane, the average value of multiple first horizontal coordinates is calculated to determine the horizontal coordinate of the actual coordinate of the terminal; when it is determined that the vehicle is located in the right lane, the average value of multiple second horizontal coordinates is calculated to determine the horizontal coordinate of the actual coordinate of the terminal.

[0106] It should be noted that, when it is determined that the vehicle is located in the left lane, the reference coordinates in the right lane are calculated based on the RSSI value with errors. For this, the horizontal coordinates of the actual coordinates of the terminal should be averaged with the horizontal coordinates of the reference coordinates in the left lane (first horizontal coordinates). Similarly, when it is determined that the vehicle is located in the right lane, the reference coordinates in the left lane are calculated based on the RSSI value with errors. For this, the horizontal coordinates of the actual coordinates of the terminal should be averaged with the horizontal coordinates of the reference coordinates in the right lane (second horizontal coordinates). In this way, by excluding the error coordinates and calculating the average value, the impact of the RSSI value error on vehicle positioning can be reduced, and the accuracy of positioning can be improved.

[0107] Since the original RSSI (received signal strength indication) data fluctuates greatly and is unstable, filtering is essential to improve the accuracy of the data. However, unlike traditional indoor positioning scenarios, the amount of data that can be received at each location is very limited when the vehicle is driving at high speed, and the RSSI value will continue to change as the vehicle moves. Therefore, traditional methods such as mean filtering and Gaussian filtering are not effective in this case.

[0108] refer to Figure 3 In one embodiment of the present application, the step of obtaining multiple groups of RSSI values ​​between the multiple Bluetooth beacons in the positioning area where the vehicle enters and the terminal includes:

[0109] Step S110: Obtain the RSSI measurement value at the current moment;

[0110] It should be noted that the RSSI measurement value at the current moment is the RSSI value actually obtained at the current moment. For example, assuming that the scanning period of the terminal is 0.3 seconds, and the Bluetooth beacon periodically sends a Bluetooth broadcast signal every 0.1 seconds, the RSSI measurement value obtained at the current moment is the RSSI value determined by the terminal based on the Bluetooth broadcast signal sent by the Bluetooth beacon at 0.2 seconds, the previous moment is the RSSI value determined by the terminal based on the Bluetooth broadcast signal sent by the Bluetooth beacon at 0.1 seconds, and the next moment is the RSSI value determined by the terminal based on the Bluetooth broadcast signal sent by the Bluetooth beacon at 0.3 seconds.

[0111] Step S120: Calculate the RSSI prediction value at the next moment based on the RSSI measurement value at the current moment and the RSSI prediction change rate at the current moment;

[0112] It should be noted that the RSSI predicted change rate at the current moment is the best estimate of the rate of change of the RSSI value over time at the current moment. The RSSI predicted value at the next moment is a reasonable estimate of the RSSI value obtained at the next moment based on the RSSI measurement value at the current moment and the RSSI predicted change rate at the current moment, which helps to prepare in advance and reduce the impact of noise, especially when the vehicle speed is fast. For example, assuming that the RSSI measurement value at the current moment is -60dBm, the RSSI predicted change rate at the current moment is 4dBm / S, and the time step (the period for the Bluetooth beacon to send the Bluetooth broadcast signal) is 0.1 seconds, then the RSSI predicted value R2 at the next moment is -60+4×0.1=−56dBm.

[0113] Step S130: Obtain the RSSI measurement value at the next moment, and combine the RSSI prediction value at the next moment with the RSSI measurement value at the next moment to determine the RSSI filter value at the next moment.

[0114] It should be noted that the RSSI filter value at the next moment is a more accurate and smoother RSSI estimate calculated by combining the RSSI prediction value at the next moment and the RSSI measurement value at the next moment. By smoothing the short-term fluctuations in the RSSI data, the noise effect is reduced to avoid large fluctuations in the RSSI measurement value actually obtained at the next moment, which leads to large errors in the subsequent calculation process. The combined method includes algorithms such as weighted average or Kalman filtering to balance the weights between the two, thereby obtaining a more accurate estimate. For example, assuming that the RSSI prediction value R1 at the next moment is -60dBm, and the RSSI measurement value R2 obtained at the next moment is -58dBm, the RSSI filter value at the next moment is:

[0115] R3=a×R2+(1-a)×R1;

[0116] Where a is the gain constant, and 0<a<1. Assuming the gain constant is 0.8, R3=0.8×(-58)+(1-0.8)×(-60)=-58.4dBm. It should be noted that, considering the nonlinearity and uncertainty of the RSSI value, the filtering effect can be further optimized by introducing the adaptive adjustment gain constant a.

[0117] In this embodiment, reference Figure 5 , the method for obtaining the RSSI predicted change rate at the current moment includes:

[0118] Step S121: determining a change value of the RSSI prediction change rate at the current moment according to the RSSI prediction value at the previous moment and the RSSI filter value at the previous moment;

[0119] It should be noted that when the current moment is the RSSI value obtained by the terminal at the first moment of the scanning cycle, the RSSI prediction value of the previous moment can be obtained by analyzing historical data, and the average value, median or other statistical characteristics of the RSSI prediction values ​​of multiple moments in history are calculated and used as the initial prediction value. In the absence of any historical data, the RSSI prediction value of the previous moment is set to a reasonable default value or initial estimate, which can be selected according to the typical RSSI range, environmental characteristics or empirical values ​​of the Bluetooth beacon. Since there is no previous prediction or filtering result for reference at the first moment, the RSSI filtering value of the previous moment can be set to the RSSI measurement value actually obtained at the first moment. The change value of the RSSI prediction change rate at the current moment refers to how much the RSSI prediction change rate at the current moment has changed relative to the RSSI prediction change rate at the previous moment, reflecting the change trend of the RSSI value at two consecutive time points of the previous moment and the current moment.

[0120] For example, assuming that the RSSI prediction value R2 at the previous moment is -60dBm, and the RSSI filter value R3 at the previous moment is -58.4dBm, then the change value of the RSSI prediction change rate at the current moment is b(R3-R2) / t, where b is the gain constant and t is the time step. Assuming b=0.2 and t is 0.1S, the change value of the RSSI prediction change rate at the current moment is 0.2(-58.4+60) / 0.1=3.2dBm / S. It should be noted that, considering the nonlinearity and uncertainty of the RSSI value, the change value of the RSSI prediction change rate at the current moment can be further optimized by introducing the adaptive adjustment gain constant b.

[0121] Step S122: Add the change value of the RSSI predicted change rate at the current moment to the RSSI predicted change rate at the previous moment to determine the RSSI predicted change rate at the current moment.

[0122] It should be noted that the change value of the RSSI prediction change rate at the current moment is the difference between the RSSI prediction change rate at the current moment and the RSSI prediction change rate at the previous moment, so the RSSI prediction change rate at the current moment is equal to the sum of the change value of the RSSI prediction change rate at the current moment and the RSSI prediction change rate at the previous moment. For example, assuming that the change value of the RSSI prediction change rate at the current moment is 3.2dBm / S, and the RSSI prediction change rate at the previous moment is 2dBm / S, the RSSI prediction rate at the current moment is 5.2dBm / S.

[0123] When the terminal collects Bluetooth broadcast signals, it is easy for the Bluetooth broadcast signal to be lost due to channel occupation, differences in the receiving end, or reception delays. At the same time, the amount of Bluetooth broadcast signals received by the vehicle during high-speed movement is limited. If the lost value is not supplemented, insufficient reception data will result in a decrease in positioning accuracy.

[0124] In one embodiment of the present application, reference Figure 6 , the step of obtaining multiple groups of RSSI values ​​between the multiple Bluetooth beacons in the positioning area where the vehicle enters and the terminal comprises:

[0125] Step S140: Detecting the multiple groups of RSSI values ​​to determine the status of each group of RSSI values;

[0126] Among them, the status includes lost status and complete status;

[0127] It should be noted that the terminal assigns a timestamp or serial number to each set of received RSSI values ​​in order to track the order and time of data reception. After a scanning cycle, the terminal checks the recorded data set to determine whether there are RSSI values ​​that are expected to be received but not received. For example, this can be achieved by comparing the timestamps or serial numbers of adjacent data points. If the terminal does not receive an RSSI value from a Bluetooth beacon within a specific time window, or the received data is obviously not as expected (for example, one of the received RSSI values ​​is less than the minimum threshold), the group of RSSI values ​​can be considered to be in a lost state.

[0128] Step S150: when it is determined that the state of any group of RSSI values ​​is in a lost state, an average value of the RSSI value of the previous group and the RSSI value of the next group is calculated to compensate for the lost RSSI value.

[0129] In this embodiment, the distance relationship between the vehicle and the Bluetooth beacon during the movement process is from far to near and then to far, so the RSSI value is constantly changing, with a pattern of from small to large and then to small, and the change trend between adjacent RSSI values ​​is the same, so the average value of the two RSSI values ​​before and after the lost value can be used to supplement it.

[0130] When multiple Bluetooth beacons are set up in scenarios with less traffic, such as on mountain roads, underground garages, etc., or when the lane is in non-peak hours, the vehicle density is not high and vehicles occasionally pass by. If multiple Bluetooth beacons are always in operation, unnecessary power consumption will be increased. Long-term continuous operation will significantly shorten the battery life of the Bluetooth beacon, requiring more frequent battery replacement, which not only increases maintenance costs, but also requires a lot of manpower and time costs to replace the battery, thus affecting the stability and reliability of the entire system.

[0131] In one embodiment of the present application, the positioning system further includes a plurality of detection areas, which are sequentially arranged on the lane along the length direction of the lane; the detection area includes a first infrared receiver, a second infrared receiver and an infrared transmitter located on the same straight line, and the straight line forms a preset angle with the straight line in the length direction of the lane; the infrared transmitter is arranged on the middle dividing line and is located adjacent to adjacent positioning areas, or at non-adjacent positions of the positioning areas; the first infrared receiver is arranged on the left boundary line, and the second infrared receiver is arranged on the right boundary line; wherein the positioning area where the first infrared receiver is located is the next positioning area after the positioning area where the second infrared receiver is located; the positioning method further includes:

[0132] When any one of the first infrared receivers is triggered, control a plurality of the Bluetooth beacons in a previous location zone of the location zone where the first infrared receiver is located to send Bluetooth broadcast signals;

[0133] When any one of the second infrared receivers is triggered, control a plurality of the Bluetooth beacons in a subsequent location zone of the location zone where the second infrared receiver is located to send Bluetooth broadcast signals;

[0134] When any one of the first infrared receivers is not triggered, the plurality of Bluetooth beacons in the previous positioning zone of the positioning zone where the first infrared receiver is located are controlled to stop working;

[0135] When any one of the first infrared receivers is not triggered, the plurality of Bluetooth beacons in the next positioning zone where the first infrared receiver is located are controlled to stop working.

[0136] It should be noted that the reference Fig.10The straight line where the infrared transmitter, the first infrared receiver and the second infrared receiver are located forms a preset angle (for example, 60°) with the length direction of the lane. When the vehicle is about to enter the next positioning area (the positioning area composed of ④~⑨ Bluetooth beacons) in the right lane, it will first pass through the straight line (detection area) where the infrared transmitter and the second infrared receiver of the current positioning area (the positioning area composed of ①~⑥ Bluetooth beacons) are located. When the second infrared receiver cannot receive the infrared light emitted by the infrared transmitter, the main control module controls multiple Bluetooth beacons in the next positioning area (the positioning area composed of ④~⑨ Bluetooth beacons) of the positioning area (the positioning area composed of ①~⑥ Bluetooth beacons) where the second infrared receiver is located to send Bluetooth broadcast signals. For another example, when a vehicle is about to enter the positioning area composed of Bluetooth beacons ①~⑥ in the left lane, the vehicle blocks the infrared rays emitted by the infrared transmitter. When the main control module detects that the first infrared receiver has not received the infrared rays, it controls the multiple Bluetooth beacons in the previous positioning area (the positioning area composed of Bluetooth beacons ①~⑥) of the positioning area where the first infrared receiver is located (the positioning area composed of Bluetooth beacons ④~⑨), to send Bluetooth broadcast signals, so as to establish a communication connection with the terminal in advance, so as to avoid the terminal being unable to receive and process Bluetooth broadcast signals in time due to the high speed of the vehicle. With this setting, the multiple Bluetooth beacons in the positioning area will only work when the vehicle is about to enter, and stop working in other cases, thereby reducing unnecessary working time and load, extending the life of the Bluetooth beacons, and reducing the frequency of battery replacement, thereby reducing maintenance costs and labor costs. And because Bluetooth beacons include microcontrollers, BLE chips, antennas and other devices, while infrared transmitters or infrared receivers only include infrared LEDs, photodiodes and some basic circuits, the cost of Bluetooth beacons is much higher than that of infrared transmitters or infrared receivers. By reducing the number of working times of Bluetooth beacons and extending the life of Bluetooth beacons, the number of times they need to be replaced during use can be reduced, thereby reducing costs.

[0137] refer to Figure 7 In one embodiment of the present application, the positioning method further includes:

[0138] Step S500: establishing a variation curve of RSSI values ​​between a plurality of the Bluetooth beacons in a plurality of the positioning areas and the terminal;

[0139] Step S600: When the RSSI value between any one of the Bluetooth beacons and the terminal reaches a maximum value, it is determined that the vehicle enters the positioning area where the Bluetooth beacon whose RSSI value reaches the maximum value is located.

[0140] In this embodiment, since the distance of the vehicle relative to a single Bluetooth beacon changes from far to near and then to far, the change trend of the RSSI value is to increase first and then decrease, so it is possible to determine whether the vehicle has entered the positioning unit by judging the maximum value of the RSSI value. When the RSSI value of one of the Bluetooth beacons reaches the maximum value, it can be determined that the vehicle has entered the positioning area where the Bluetooth beacon is located. At this time, the terminal stops processing the RSSI value of the Bluetooth beacon in the previous positioning area and processes the RSSI value of the Bluetooth beacon in the positioning area. With this setting, the coordinate position of the vehicle during driving can be updated in real time.

[0141] Based on the above embodiment of step 330, refer to Figure 8 , the fusing the N centroid coordinates to determine the reference coordinates of the terminal includes:

[0142] Step S331: determining weighting factors of the N combinations based on the distances between the three Bluetooth beacons of the N combinations and the terminal;

[0143] The weighting factor can be the reciprocal of the distance, the reciprocal of the distance squared, or other functions inversely proportional to the distance to reflect the impact of distance on positioning accuracy. For example, the distances between the three Bluetooth beacons in one combination and the terminal are d1, d2, and d3, respectively. The weighting factors W1, W2, and W3 corresponding to d1, d2, and d3 are W1=d1 / (d1+d2+d3), W2=d2 / (d1+d2+d3), and W3=d3 / (d1+d2+d3), respectively.

[0144] Step S332: combining the N combined weighting factors with the abscissas and ordinates of the N centroid coordinates one by one, respectively, to determine N weighted abscissas and N weighted ordinates;

[0145] The weighted horizontal coordinate X is calculated according to the following formula Q and weighted ordinate Y Q :

[0146] and ; Wherein, Wi is the weighting factor of the i-th combination, Xi is the horizontal coordinate of the i-th center of mass coordinate, and Yi is the vertical coordinate of the i-th center of mass coordinate.

[0147] It should be noted that by assigning different weights to each centroid coordinate and adjusting its influence on the reference coordinate estimate accordingly, the negative impact of measurements with large errors on the results can be effectively reduced. For example, if the signal of a Bluetooth beacon is weakened due to environmental factors (such as wall occlusion), resulting in an inaccurate distance estimate, then its corresponding centroid coordinate will be assigned a lower weight and play a smaller role in the final calculation.

[0148] Step S333: Calculate the average value of the N weighted horizontal coordinates and the average value of the N weighted vertical coordinates respectively to determine the reference coordinates of the terminal.

[0149] It can be understood that the abscissa of the reference coordinates of the terminal is the average value of the N weighted abscissas, and the ordinate is the average value of the N weighted ordinates.

[0150] The present application provides a positioning system, which includes: at least one processor; and a memory that is communicatively connected to the at least one processor; wherein the memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the positioning method in the above-mentioned embodiment 1; the positioning system also includes multiple positioning areas and a terminal arranged in a vehicle, and the multiple positioning areas are arranged in sequence on the lane, and the positioning areas include multiple Bluetooth beacons respectively installed on the left boundary line, the middle dividing line and the right boundary line of the lane, and the terminal establishes a Bluetooth communication connection with the multiple Bluetooth beacons.

[0151] The positioning system provided by the present application adopts the positioning method in the above embodiment, which can solve the technical problem that the vehicle cannot be accurately positioned when entering a scene blocked by an obstruction. Compared with the prior art, the beneficial effects of the positioning system provided by the present application are the same as the beneficial effects of the positioning method provided by the above embodiment, and the other technical features of the positioning system are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0152] It should be understood that the various parts disclosed in this application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0153] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0154] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A positioning method, applied to a positioning system, characterized in that: The positioning system includes a plurality of positioning areas and a terminal arranged in a vehicle, wherein the plurality of positioning areas are arranged in sequence on a lane along the length direction of the lane, the positioning area includes a plurality of Bluetooth beacons respectively installed on a left boundary line, a middle dividing line and a right boundary line of the lane, the terminal establishes a Bluetooth communication connection with the plurality of Bluetooth beacons, and the method includes: Acquire multiple groups of RSSI values ​​between the multiple Bluetooth beacons in the positioning area where the vehicle enters and the terminal; Determine the distances between the multiple groups of Bluetooth beacons and the terminal according to the multiple groups of RSSI values; Determining multiple reference coordinates of the terminal according to the distances between the multiple groups of Bluetooth beacons and the terminal; Determining the actual coordinates of the terminal according to the plurality of reference coordinates; Wherein, the positioning area includes at least six Bluetooth beacons; Determining the actual coordinates of the terminal according to the multiple reference coordinates includes: Calculate the difference between the horizontal coordinates of the reference coordinates and the horizontal coordinates of the Bluetooth beacon located on the left boundary line and the horizontal coordinates of the Bluetooth beacon located on the right boundary line to determine a plurality of first horizontal distances and a plurality of second horizontal distances; comparing a plurality of the first lateral distances and a plurality of the second lateral distances with a lane width respectively; When the first lateral distance corresponding to any one of the reference coordinates is smaller than the lane width and the corresponding second lateral distance is larger than the lane width, a first count is performed and the abscissa of the reference coordinate is marked as a first abscissa; When the first lateral distance corresponding to any one of the reference coordinates is greater than the lane width and the corresponding second lateral distance is less than the lane width, performing a second count and marking the abscissa of the reference coordinate as a second abscissa; When the ratio of the value of the first count to the number of the reference coordinates is greater than a preset percentage, it is determined that the vehicle is located in the left lane; when the ratio of the value of the second count to the number of the reference coordinates is greater than a preset percentage, it is determined that the vehicle is located in the right lane; When it is determined that the vehicle is located in the left lane, calculating an average value of a plurality of the first horizontal coordinates to determine the horizontal coordinate of the actual coordinate of the terminal; When it is determined that the vehicle is located in the right lane, an average value of a plurality of the second horizontal coordinates is calculated to determine the horizontal coordinate of the actual coordinate of the terminal.

2. The positioning method according to claim 1, characterized in that: The step of obtaining multiple groups of RSSI values ​​between the multiple Bluetooth beacons in the positioning area where the vehicle enters and the terminal comprises: Get the RSSI measurement value at the current moment; Based on the RSSI measurement value at the current moment and the RSSI predicted change rate at the current moment, calculate the RSSI predicted value at the next moment; The RSSI measurement value at the next moment is obtained, and the RSSI prediction value at the next moment is combined with the RSSI measurement value at the next moment to determine the RSSI filter value at the next moment.

3. The positioning method according to claim 2, characterized in that: The method for obtaining the RSSI predicted change rate at the current moment includes: Determine the change value of the RSSI prediction change rate at the current moment according to the RSSI prediction value at the previous moment and the RSSI filter value at the previous moment; The change value of the RSSI predicted change rate at the current moment is added to the RSSI predicted change rate at the previous moment to determine the RSSI predicted change rate at the current moment.

4. The positioning method according to claim 1, characterized in that: The step of obtaining multiple groups of RSSI values ​​between the multiple Bluetooth beacons in the positioning area where the vehicle enters and the terminal comprises: Detecting the multiple groups of RSSI values ​​to determine the state of each group of RSSI values; wherein the state includes a lost state and a complete state; When it is determined that any one group of RSSI values ​​is lost, an average value of the RSSI value of the previous group and the RSSI value of the subsequent group is calculated to compensate for the lost RSSI value.

5. The positioning method according to claim 1, characterized in that: The positioning system further comprises a plurality of detection areas, which are sequentially arranged on the lane along the length direction of the lane; the detection area comprises a first infrared receiver, a second infrared receiver and an infrared transmitter located on the same straight line, and the straight line forms a preset angle with the straight line in the length direction of the lane; the infrared transmitter is arranged on the middle dividing line and is located at adjacent positions of adjacent positioning areas, or at non-adjacent positions of the positioning areas; the first infrared receiver is arranged on the left boundary line, and the second infrared receiver is arranged on the right boundary line; wherein the positioning area where the first infrared receiver is located is the next positioning area after the positioning area where the second infrared receiver is located; The positioning method further includes: When any one of the first infrared receivers is triggered, control the plurality of Bluetooth beacons in the previous location zone of the location zone where the first infrared receiver is located to send Bluetooth broadcast signals; When any one of the second infrared receivers is triggered, control a plurality of the Bluetooth beacons in a subsequent location zone of the location zone where the second infrared receiver is located to send Bluetooth broadcast signals; When any one of the first infrared receivers is not triggered, the plurality of Bluetooth beacons in the previous positioning zone of the positioning zone where the first infrared receiver is located are controlled to stop working; When any one of the first infrared receivers is not triggered, the plurality of Bluetooth beacons in the next positioning zone where the first infrared receiver is located are controlled to stop working.

6. The positioning method according to claim 1, characterized in that: The positioning method further includes: Establishing a change curve of RSSI values ​​between the plurality of Bluetooth beacons in the plurality of positioning areas and the terminal; When the RSSI value between any one of the Bluetooth beacons and the terminal reaches a maximum value, it is determined that the vehicle enters the positioning area where the Bluetooth beacon whose RSSI value reaches the maximum value is located.

7. The positioning method according to claim 1, characterized in that: Determining a plurality of reference coordinates of the terminal according to the distances between the plurality of groups of Bluetooth beacons and the terminal comprises: Randomly select three Bluetooth beacons that are not in the same straight line from the plurality of Bluetooth beacons as a group, and determine N combinations; The distances between the three Bluetooth beacons in N combinations and the terminal are processed based on the three-side centroid positioning algorithm to determine N centroid coordinates; The N centroid coordinates are fused to determine the reference coordinates of the terminal.

8. The positioning method according to claim 7, characterized in that: The fusing the N centroid coordinates to determine the reference coordinates of the terminal includes: Determine weighting factors of the N combinations based on the distances between the three Bluetooth beacons of the N combinations and the terminal; Combining the N combined weighting factors with the abscissas and ordinates of the N centroid coordinates one by one, respectively, to determine N weighted abscissas and N weighted ordinates; An average value of the N weighted horizontal coordinates and an average value of the N weighted vertical coordinates are calculated respectively to determine the reference coordinates of the terminal.

9. A positioning system, characterized in that: include: A memory, a host computer and a computer program stored in the memory and executable on the host computer, wherein the computer program is configured to implement the steps of the positioning method according to any one of claims 1 to 8; the positioning system further comprises a plurality of positioning areas and a terminal arranged in a vehicle, wherein the plurality of positioning areas are arranged in sequence on a lane, the positioning area comprises a plurality of Bluetooth beacons respectively installed on the left boundary line, the middle dividing line and the right boundary line of the lane, and the terminal establishes a Bluetooth communication connection with the plurality of Bluetooth beacons.

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